MIPS: Alchemy: Fix up residual devboard poweroff/reboot code.

Clean out stray unused board_reset() calls in pb1x boards, the PB1000 is
different from the rest and gets private methods.

(Cleanup after 32fd6901)

Signed-off-by: Manuel Lauss <manuel.lauss@gmail.com>
To: Linux-MIPS <linux-mips@linux-mips.org>
Patchwork: http://patchwork.linux-mips.org/patch/1085/


Signed-off-by: Ralf Baechle <ralf@linux-mips.org>